Micro and nano-scale manipulation and assembly techniques have become more important in many industries in recent years, as the fabrication of smaller systems has become more desirable. Some researchers have addressed this micro and nano-scale manipulation and assembly issue by investigating non-contact manipulation and assembly techniques, such as by levitating components (i.e. through the use of electromagnetic and optical tweezers, for example). Currently, the major limitation or challenge with respect to these electromagnetic and optical tweezers is the size of the devices themselves. Electromagnetic and optical tweezers are often relatively large and, as a result, their applicability is limited to relatively large unobstructed areas, with limited ability to manipulate or place objects in or relative to features such as narrow channels and cavities.
For any manipulation and assembly technique, there is a need for force detection capability integral with the gripping mechanism. The objective is to enable force feedback in order to detect the presence of components and prevent damage to the fragile components. For example, micro-mirrors in the assembly of optical switches typically break when the gripping forces exceed a few micro-Newtons. As a result, micro-manipulator technologies require sensing capability in order to provide force feedback, with maximum applied forces less than this threshold. For example, one device has been developed that has the ability to sense force, but the micro-sensor is static and, therefore, still susceptible to attraction forces between the micro-manipulator and the specimen or component. In general, self-sensing tweezers with the ability to overcome attraction forces and incorporating force sensing would lead to new manufacturing and assembly process capabilities and, therefore, lower production costs.